We're working on cleaning our Marketo database. We have our database synced with Salesforce. Other sources are list upload, web APIs and web forms.

We're evaluating the possible leads/contacts that can be removed from our Marketo database. A major chunk of these are globally opted out contacts. Is it fine to remove them from the Marketo database? If anyone has worked on such a database cleaning project, what are the major buckets of leads/contacts that can be removed from the Marketo database?

Shashank, these are the people I would 100% not remove from the database, it's very important that you keep all unsubscribers as you have to have a record of them so they never get emailed accidentally. I'll give you a scenario, say you go ahead and delete these people, then someone on your team uploads an old list, an unsubscribed person could then potentially get added back into the database and email from you, which breaches CAN-SPAM laws.

If you want to decrease your database size, I suggest running the following clean-up campaigns:

Jackie is correct, Marketo remembers an unsubscribed person even if you delete, I was always was too scared to take the chance (tested and it works). This means if you delete them and they enter back into the system, they will be auto unsubscribed.

We like to keep our unsubscribers in the system so we keep the Munchkin code running and also on occasion they turn back into a subscriber or new business.